The leaves are falling off the leaves in torrents now. Go for a walk and they are wind-driven into piles of gold and scarlet and ruby and cinnamon brown. They look as if some Florentine tailor has just dropped his pack of velvets and is running for his life.

When I was small, this was the time of year when the elves’ paths in the woods were suddenly revealed. Where there had been a dense wall of foliage in summer, suddenly there were overgrown, narrow tracks, barely wide enough for an adult human to squeeze through, spiking off from the main path. They led through twiggy undergrowth, round tree trunks, over streams, off into …. where?

The unknown. The place where your imagination has to sniff the air and fall back on its own devices. The Path of Scary Possibilities.

You can see bits of the path, but not all of it. You don’t know how the bits you can see fit together. You certainly can’t see where the path ends. In order to find out, you will have to bend double, and risk a scratching from twigs, being tripped up by hidden tree roots and having to ford your way through streams and mud and maybe tumble down sudden slopes …. You don’t know whether you will be able to get back. But something went this way. Can you go too?

The best writing, the most exciting reading (and watching movies, going to the theatre, hearing opera) are the same. And sometimes– be still my beating heart– among the shadows appears an enigmatic figure who may lead you somewhere magical.

For the late great Eva Ibbotson, I’m willing to lay down good money that one of these thrilling, compulsive, enigmatic shadow-heroes was Raskolnikov. For Phillipa Ashley he is actor, Richard Armitage.

In real life, Armitage appears to be a nice bloke who does a bit of DIY and is bewildered by the excesses of fans. In a televised North and South, he was a rude, truth-telling mill owner. In a rubbish Robin Hood, he was a leather-clad sadist whomade the Merrie Men of Sherwood F. look like the Much Piddling in the Marsh Under Eighteen Glee Club. Currently– possibly for one more week only– he is Lucas North in the BBC series Spooks– half Mephistopheles, half Scarlet Pimpernel.

Spooks is one of those programmes where they do Tension by the bucketful. To my shame, I find there is a constant possibility of retreating behind the sofa to cower. Every time it’s on, I say to myself, ‘Can I bear to watch this week?’ Sometimes, I can’t.

And this series the writers (brilliant or what?) have upped the ante by making Lucas North by turns good guy, bad guy, good guy, bad- oh no-o-o-o-o-o really-evil-guy.

And, by golly, Mr Armitage has pulled out the stops for them. I’m an impatient TV-watcher. By now, I would have expected to say, ‘Sod it, I can’t keep up. I can’t be bothered with this.’ Mr Armitage keeps me bothered, keeps me hoping-against-hope. Keeps me, in fact, walking down that mysterious path to who-knows-where with all my antennae on full alert.

Makes me feel alive, in other words.

How?

The point about Mr Armitage, it seems to me, is he is serious. Alison Pearson thinks it’s because he’s a grown-up, and there is much in what she says.

But I think it’s more than that. He plays his characters with a sort of options-closed-off intensity that drags you in, too. Even if you’re a congenital hedger of bets, even if you’re the sort of person that uses comparison websites, makes reasoned judgements, doesn’t get too involved with messy emotions or irrational desires. Yes, even you will still have a bit of your imagination that knows those elven paths are there. Dangerous, untrustworthy, challenging as they are, they might just take you to a Different You.

And one of Mr Armitage’s characters might just point the way. After all, he turned Phillipa Ashley into a successful romantic novelist.